Column heater



FIG. 1 is a perspective view of a column heater showing our new design;

FIG. 2 is a front elevation view of the column heater;

FIG. 3 is a back elevation view of the column heater;

FIG. 4 is a top plan view of the column heater; and,

FIG. 5 is a bottom plan view of the column heater.

The broken lines indicate unclaimed portions of the article that form no part of the claimed design. 

CLAIM The ornamental design for a column heater, as shown and described. 